Each year, over 230,000 people survive moderate and severe traumatic brain injury (TBI). As a result, a large number of individuals with TBI endure life-long impairment and disability. Memory disturbance is one of the most disabling consequences of TBI, but there has been little focused research on the cerebral mechanisms of impaired memory after TBI. The Research Plan for the National Center for Medical Rehabilitation Research (NCMRR) points to the need to "evaluate the efficacy of neuroimaging techniques," and to "develop new and precise quantitative measures of impairment" after traumatic brain injury (TBI). The present proposal will address these goals by applying functional MRI (FMRI) to study impairment in episodic memory (i.e., encoding and recognition) after TBI. Preliminary data demonstrate that persons with TBI have altered cerebral representation of episodic and working memory relative to controls. What is not known, however, are the cerebral substrates of impaired encoding and recognition after TBI, and how higher-order aspects of cognitive impairment (e.g., executive control dysfunction, which is pervasive after TBI) might impact these memory functions. We will use BOLD FMRI to examine the effects of TBI on episodic memory tasks using paradigms that have been established among healthy individuals. Participants will be 40 persons that are approximately 1 to 3 years post moderate-to-severe TBI, and 20 healthy controls. Because cognitive effort underlies FMRI activations during memory tasks, it is expected that as task demands increase, individuals with TBI will show more widespread cerebral activations than healthy controls. This effect is expected to be greatest among individuals with TBI that have significant executive control impairments. It is expected that individuals with TBI will show greater intensity and regional dispersion of cerebral activation, even at simpler levels of memory processing, suggesting changes in the cerebral substrates of episodic memory following TBI. The results of the present study will provide a better understanding of the specific mechanisms of episodic memory and may provide improved tools for assessing behavioral and pharmacological interventions for memory impairment after brain injury. [unreadable] [unreadable]